The purpose of this paper is to provide users with the results of an investigation into the impact of stratification changes that took place between the conduct of the 2003 and 2004 Surveys of Motor Vehicle Use (SMVU).

In releasing the 2004 SMVU estimates, the Australian Bureau of Statistics (ABS)identified that the stratification change, introduced as part of the 2004 sample design, may have caused some concerns with the coherence of the 2003 estimates. As a result, the ABS decided not to publish the 2003 estimates in the 2004 publication and indicated to users that an investigation would occur and advise of the outcome at a later date.

Following a comprehensive review of the survey's methodology, new stratums were introduced for the 2004 survey to improve the quality of the survey outputs. The main difference between the stratification used in 2004 and that used in 2003 was that more emphasis was placed on age of vehicle in 2004. Area of operation was dropped as a stratification variable for all vehicle types.

To investigate concerns regarding coherence, the ABS compiled new estimates from the 2003 reference year survey data using the stratification groups applied to the 2004 reference year.

A comparison of the two sets of estimates was undertaken. The differences were small and did not indicate any systemic quality concern with the 2003 stratification and estimation process. For example, the original estimate for total kilometres travelled for all vehicles was 201,497 million and the estimate following post-stratification was 200,076 million, a difference of 0.7%. For this reason, the ABS does not consider it necessary to re-release the 2003 SMVU estimates. The official 2003 estimates are those contained in the publication Survey of Motor Vehicle Use, Australia, 2003 (cat. no. 9208.0).

For the information of users, the following summary tables present the 2003 post-stratified estimates.

Table 1: Summary of Motor Vehicle Use, Type of Vehicle

2000

2001

2002

2003(a)

2004

Total kilometres travelled (million)

Passenger vehicles

141 519

143 925

144 676

150 505

147 728

Motor cycles

1 135

1 448

1 681

1 371

1 478

Light commercial vehicles

27 829

30 728

31 349

32 670

34 007

Rigid trucks

6 536

6 627

7 080

7 730

7 639

Articulated trucks

5 578

5 321

5 425

5 716

6 013

Non-freight carrying trucks

^220

^267

224

202

221

Buses

1 776

1 835

1 775

1 882

1 968

Total

184 593

190 152

192 209

200 076

199 055

Number of vehicles(b) (number)

Passenger vehicles

9 711 320

9 861 807

10 194 637

10 393 312

10 654 328

Motor cycles

337 793

349 465

367 258

378 631

392 648

Light commercial vehicles

1 696 631

1 719 654

1 810 071

1 896 498

1 940 180

Rigid trucks

346 628

332 102

341 651

346 380

358 704

Articulated trucks

61 117

61 502

61 519

62 888

66 197

Non-freight carrying trucks

18 714

18 980

17 504

17 837

17 616

Buses

55 805

55 078

56 754

59 819

61 728

Total

12 228 008

12 398 588

12 849 393

13 155 365

13 491 401

Average kilometres travelled(c) ('000)

Passenger vehicles

14.6

14.6

14.2

14.5

13.9

Motor cycles

3.4

4.1

4.6

3.6

3.8

Light commercial vehicles

16.4

17.9

17.3

17.2

17.5

Rigid trucks

18.9

20.0

20.7

22.3

21.3

Articulated trucks

91.3

86.5

88.2

90.9

90.8

Non-freight carrying trucks

^11.8

14.1

12.8

11.3

12.5

Buses

31.8

33.3

31.3

31.5

31.9

Total

15.1

15.3

15.0

15.2

14.8

Total fuel consumption (million litres)

Passenger vehicles

16 838

16 436

16 401

17 195

16 937

Motor cycles

70

83

100

83

^92

Light commercial vehicles

3 723

4 186

4 145

4 271

4 471

Rigid trucks

1 795

1 855

2 041

2 183

2 123

Articulated trucks

2 904

2 824

2 922

3 091

3 305

Non-freight carrying trucks

^57

67

58

52

53

Buses

466

498

497

517

524

Total

25 853

25 948

26 164

27 391

27 505

Average rate of fuel consumption(d) (litres per 100 kilometres)

Passenger vehicles

11.9

11.4

11.3

11.4

11.5

Motor cycles

6.1

5.7

6.0

6.1

6.3

Light commercial vehicles

13.4

13.6

13.2

13.1

13.1

Rigid trucks

27.5

28.0

28.8

28.2

27.8

Articulated trucks

52.1

53.1

53.9

54.1

55.0

Non-freight carrying trucks

25.9

25.0

26.0

25.7

24.0

Buses

26.2

27.1

28.0

27.5

26.6

Total

14.0

13.6

13.6

13.7

13.8

^ Estimate has a relative standard error of 10% to less than 25% and should be used with caution.(a) Post-stratified estimates. For official estimates refer to Survey of Motor Vehicle Use October 2003 Cat no. 9208.0.(b) The average number of vehicles registered for the 12 months. Includes registered vehicles that did not travel during the reference period.(c) Calculated using average number of registered vehicles. Includes registered vehicles that did not travel during the reference period.(d) Calculated using the total fuel consumption divided by the total kilometres travelled.

Table 2: Summary of Freight Vehicle Use, Type of Vehicle

2000

2001

2002

2003(a)

2004

Total laden business kilometres travelled (million)

Light commercial vehicles

13 120

13 889

14 054

15 326

15 844

Rigid trucks

4 537

4 690

4 830

5 387

5 322

Articulated trucks

4 071

3 933

4 012

4 298

4 367

Total freight vehicles

21 728

22 512

22 896

25 011

25 533

Average laden business kilometres travelled(b) ('000)

Light commercial vehicles

14.7

15.3

14.0

14.8

14.4

Rigid trucks

16.1

16.3

16.2

17.5

16.8

Articulated trucks

72.8

69.6

70.4

74.5

71.4

Total freight vehicles

17.7

18.0

16.8

17.9

17.2

Total tonne-kilometres travelled (million)

Light commercial vehicles

5 695

5 649

5 624

6 701

6 634

Rigid trucks

25 168

24 881

28 337

30 572

29 752

Articulated trucks

103 515

101 892

106 977

112 423

121 282

Total freight vehicles

134 378

132 422

140 938

149 695

157 668

Average tonne-kilometres travelled(c) (million)

Light commercial vehicles

6.4

6.2

5.6

6.5

6.0

Rigid trucks

89.1

86.5

95.1

99.5

93.7

Articulated trucks

1 852.0

1 804.4

1 876.3

1 947.7

1 983.3

Total freight vehicles

109.3

105.8

103.5

107.0

106.4

Total tonnes carried (million)

Light commercial vehicles

103

103

115

122

120

Rigid trucks

711

683

802

712

807

Articulated trucks

655

697

747

714

769

Total freight vehicles

1 469

1 482

1 664

1 548

1 696

Average load carried per trip(d) (kilograms)

Light commercial vehicles

377

326

353

399

362

Rigid trucks

5 854

5 632

6 130

5 835

6 068

Articulated trucks

22 615

23 639

23 749

24 497

23 921

Total freight vehicles

3 471

3 180

3 404

4 566

3 421

(a) Post-stratified estimates. For official estimates refer to Survey of Motor Vehicle Use October 2003 Cat no. 9208.0.(b) Calculated using the total laden business kilometres travelled divided by the number of vehicles that travelled laden business kilometres.(c) Calculated using the total tonne-kilometres travelled divided by the number of vehicles that travelled tonne-kilometres.(d) Calculated using the total load carried divided by the total number of laden trips.

(a) Post-stratified estimates. For official estimates refer to Survey of Motor Vehicle Use October 2003 Cat no. 9208.0.(b) The average number of vehicles registered for the 12 months. Includes registered vehicles that did not travel during the reference period.(c) Calculated using the total kilometres travelled divided by the average number of registered vehicles. Includes registered vehicles that did not travel during the reference period.